Instrumentation for Rapid Inorganic Kinetics (Chemistry)

快速无机动力学仪器（化学）

• 批准号: 8710014
• 负责人: Joseph Hupp
• 金额: $ 7.5万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-09-01 至 1989-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8710014&HistoricalAwards=false
• 关键词: Instrumentation; Rapid; Inorganic; Kinetics; Chemistry

This award will support the construction of a pulse-accelerated flow spectrophotometer for use in the study of rapid light-induced electron transfer reactions. This type of instrumentation allows the recording of spectra for species with lifetimes as short as 1/100,000-th of a second and the measurement of rates of reactions which occur over such a short time span, but is not yet commercially available. Nearly all light-driven energy conversion processes rely at some point on electron transfer reactions, including photosynthesis. One of the most promising schemes for the use of synthetic substances for light-driven energy conversion involves the use of molecules containing two metals. The absorption of light causes an electron to be transferred between the metal atoms to create a high energy molecule from which electrical or chemical energy may be extracted as the electron returns to its preferred location. Two new approaches are being used in this project for the direct assessment of thermal intramolecular electron transfer rates. The first of these makes use of preferential solvation to interconvert mixed-valence redox isomers of unsymmetrical binuclear metal complexes. Pulse accelerated flow spectrophotometry is being used to time-resolve the redox isomerization process. The second approach is based on light-induced (pulsed laser) metal-to-metal charge transfer in the near IR to create high energy isomers, again in mixed-valence complexes. Relaxation by electron transfer to create low energy isomers can be followed in the visible by transient absorbance spectroscopy. This project is supported in part by a Presidential Young Investigator award.

该奖项将支持构建脉冲加速流动分光光度计，用于快速光诱导电子转移反应的研究。这种类型的仪器可以记录寿命短至 1/100,000 秒的物种的光谱，并测量在如此短的时间跨度内发生的反应速率，但尚未商业化。几乎所有光驱动的能量转换过程在某种程度上都依赖于电子转移反应，包括光合作用。使用合成物质进行光驱动能量转换的最有前途的方案之一涉及使用含有两种金属的分子。光的吸收导致电子在金属原子之间转移以产生高能分子，当电子返回到其优选位置时可以从该高能分子中提取电能或化学能。 该项目使用两种新方法来直接评估热分子内电子转移速率。其中第一个利用优先溶剂化来使不对称双核金属配合物的混合价氧化还原异构体相互转化。脉冲加速流动分光光度法用于对氧化还原异构化过程进行时间分辨。第二种方法基于近红外光诱导（脉冲激光）金属间电荷转移，以产生高能异构体，同样是混合价络合物。通过电子转移弛豫产生低能异构体，然后在可见光中通过瞬态吸收光谱进行跟踪。该项目部分得到总统青年研究员奖的支持。